Freshman Rep. Markwayne Mullin, R-Okla., might have collected outside earnings in 2013 that exceeded the cap for sitting members of Congress as he maintained a relationship with his business that he was supposed to largely sever upon being elected to office, the House Ethics Committee divulged on Monday.

The bipartisan panel announced that it would continue to review whether Mullin violated House rules before determining whether to launch an official investigation.

In making that announcement, the committee also released the findings of a 66-page report detailing, for the first time , the charges Mullin faces. That report was prepared by the quasi-independent Office of Congressional Ethics, which conducted the preliminary investigation before referring the case to the standing committee of House lawmakers.

In addition to questioning whether Mullin earned a $600,000 salary through his long-held, Oklahoma-based plumbing business — exceeding the legal limit of $26,955 as a member of the House — the OCE recommended that the Ethics Committee probe whether Mullin violated chamber rules by endorsing his business's services in TV, radio and internet advertisements. According to the OCE report, Mullin approached Ethics Committee staff shortly after his November 2012 election to discuss what he could and could not do in relation to his business. Staff determined that advertisements that Mullin had produced prior to his election could continue to circulate, but did not issue guidance on whether he could be involved in producing subsequent commercials.

Mullin reportedly told OCE investigators that he wasn't sure whether he had appeared in additional commercials for his plumbing companies since becoming a member of Congress, but said that he continues to appear on a weekly local radio program called "House Talk," a program in which he advises callers on various home repair issues.

"Markwayne personally promotes the company through television and radio advertising," his official campaign website reads . "One of his favorite jobs is to produce and host the radio call-in talk show."

The OCE also wants the Ethics Committee to review whether Mullin received compensation for serving on various boards of the five companies that make up his business.

"Representative Mullin told the OCE that he is a board member of the companies and that he has not been President or Chief Executive Officer of the companies since December 2012," the OCE report states. "However, Mullin Plumbing CFO and Mullin Plumbing Accountant told the OCE that Mullin is currently the President."

In an 11-page response to the OCE from Mullin's attorneys, which the Ethics Committee also released on Monday, the Wiley Rein lawyers denied that his client was guilty of any misconduct.

For one thing, the lawyers said, the OCE misrepresented Mullin's $600,000 earnings in 2013.

"For tax and accounting purposes, these payments were treated as distributions to Mr. Mullin," they wrote to the OCE. "Nonetheless, they were business payments and expenditures of the corporations. In fact, all checks for payments and expenditures included in the above-cited totals went directly from the paying corporations to the payees and not to Rep. Mullin."

The lawyers specify that, of that $600,000 sum, $387,425 were tax payments to the Internal Revenue Service and the Oklahoma Tax Commission; $69,983 were payments to Mullin's father for purchase of the business; and $87,702 went for the purchase of rental properties.

"Even if there had been outside income earned by Rep. Mullin in excess of the $26,955 limit in 2013, it would not have been in violation of any of the purposes or policies underlying those income limits," the lawyers argued — that is, they don't present conflicts of interest.

The Wiley Rein attorneys also emphasized that Mullin went out of his way to seek official guidance from the Ethics Committee before he was even sworn into office. In his own letter to the OCE from November 2013, Mullin made that point as well.

The OCE, however, countered that Mullin may not have, at the time, painted a full picture of his situation in discussions with the Ethics panel.